Aim: Describe the safety and effectiveness of intra-articular bone marrow concentrate (BMC) injection to treat knee and/or hip osteoarthritis (OA) in a Canadian cohort. Materials & methods: A total of 112 patients with refractory OA received a single intra-articular injection of BMC into their knee(s) and/or hip(s). Pain, disability and quality of life were prospectively assessed prior to and 3, 6 and 12 months post-injection. Results: Outcome scores were significantly improved at all time points post-BMC injection with maximal improvement observed at 3–6 months. Improvements were unrelated to patient age, sex or radiographic OA severity. The complication rate was <2%. Interpretation: In this Canadian cohort, knee/hip OA treated with a single BMC injection resulted in significant improvements in pain, disability and quality of life and a low complication rate.